"Millions of people live in properties that were used as meth labs," said Joseph Mazzuca, who co-founded Meth Lab Cleanup in Athol, Idaho, with his wife, Julie. Last year, his company booked more than 1,500 jobs inspecting and decontaminating homes. Jonathan Hankins, 32, thought that he and his wife, Beth, got a terrific deal last June on a starter home in Klamath Falls, Ore. They paid just $36,000 for a two-bedroom fixer-upper that had been repossessed in a foreclosure.

"We only lived there three weeks," said Hankins. "We started to experience symptoms." They got dry mouth, headaches and nosebleeds. Their 2-year-old son, Ezra, got mouth sores so severe that he couldn't drink. After neighbors told Hankins that the house had been a meth lab, he bought a test kit for $50. It showed meth residue at about 80 times the state's legal limit for acceptable levels of meth residue in a home after it has been cleaned.

The family moved out, and the health problems cleared up after a few weeks. But their financial problems persisted. The couple is still paying the mortgage on the house and rent on a new one, and they lost furniture and other belongings that became contaminated.

Hankins' lawyer told him to walk away from the mortgage, but he doesn't want to ruin his credit. Even if they pay to clean up the house, it would be difficult to recoup any money by selling it. Straightforward decontamination jobs can cost $5,000 to $10,000, according to Mazzuca. Surfaces must be rinsed with special detergents, rooms stripped of carpeting and other materials and meth residue must be sucked off of walls and other hidden surfaces.

Hankins is petitioning mortgage giant Freddie Mac, which sold him his home, to test all homes it sells for meth contamination, and he is speaking with the company about covering his costs. A Freddie spokesman, Brad German, said the company did not know the Hankins' home was contaminated. He said Freddie relies on local real estate agents to follow all state disclosure laws. "We encourage buyers to do any test they want," said German. "Hankins didn't test and bought the house as-is."

Making crystal meth involves a witch's brew of ordinary household products like acetone, acids, brake cleaner and iodine, which are all used to cook cold medicine containing pseudoephedrine into meth.

Bottles of paint thinner, drain opener or muriatic or other acids are strong indicators that someone has been making meth, as are propane tanks or other heat sources used to cook the drug. Sinks stained red by phosphorus, chemical smells and powdery residues left in glass cookware are also telltale signs.

Meth users tend to lead messy lives with lasting effects that linger long after they leave.

For every pound of meth produced, five to seven pounds of chemical waste is left behind. Those residues can cause a litany of health problems, including breathing issues, skin irritation, headaches, nausea and dizziness. Over a long period, liver and kidney damage, neurological problems, and increased risk of cancer can occur, according to the Minnesota Department of Health.

To find out if a home is contaminated, homeowners can buy test kits for about $55 from Meth Lab Cleanup and other companies. If test results are positive, then homeowners can hire a professional testing and remediation firm to determine the scope of the problem.

The company will take wipe samples in various parts of the house. Testing the whole house usually runs between $500 and $700 but can cost more for larger homes and more complicated jobs.

The cleanup can run from a couple thousand dollars to $10,000 or more. Some homes have been so badly contaminated that owners choose to demolish the home instead.

Meth's harmful molecules can be re-emitted for months or even years, according to Glenn Morrison, an associate professor of environmental engineering at Missouri University of Science and Technology.

Ridding the home's interior of these harmful residues requires rinsing the walls, ceilings and floors with a special cleaning solution several times, according to Joe Mazzuca, co-founder of Meth Lab Cleanup. In addition, his company uses a "negative air" process that sucks out residue from hidden spaces.

Chemical vapors can penetrate soft surfaces like carpets and drapes, requiring cleanup crews to strip those materials from the home and dispose of them.

Meth contamination can also extend beyond a home's walls. Meth users often dump used paraphernalia in nearby woods or lots and these areas need to be decontaminated as well.

Meth residue can not only coat the surfaces of a home, but invade duct work, attics and hollow spaces as well. It can sometimes even penetrate sheetrock, which then has to be pulled out and replaced.

Of all the dangerous chemical residues left behind in lab sites, meth molecules are the most difficult to eradicate. "If you get rid of that, you can get rid of everything else," said Mazzuca.